1)Would the table always be the same size (same number of letters)
2)What is the intend of the process (is for a game of some sort)?
3)When you say one letter at a time do you mean the user will have to click the button everytime to get a new letter or do you mean starting to show the letters one at a time with a slight delay in between?
4)From where are the letters coming, are the words kept in a database?
5)Are you using a server side language like php or is it Javascript etc.?